The toString method must be implemented in a POJO class. The super.toString method should be called in front of the whole implementation if the current class extends another POJO class.
<p>Examples:</p>
<pre>
    public class ToStringDemo extends Super{
        private String secondName;
        @Override
        public String toString() {
            return super.toString() + "ToStringDemo{" + "secondName='" + secondName + '\'' + '}';
        }
    }
    class Super {
        private String firstName;
        @Override
        public String toString() {
            return "Super{" + "firstName=" + firstName + '\'' + '}';
        }
    }
</pre>